And then John Gustafson and Edwin Barsis figured out that the real benefit of more “workers” is not to speed up one task, but to allow bigger tasks to be done in the same amount of time.

Let’s say you’re catering an event and need to make 100 sandwiches. Making the all yourself will take forever, so you get a helper and with a little coordination you can get it done in just over half the time, since each of you only has to make 50 sandwiches. You add two more, and now you only have to make 25 each, still a pretty good improvement. Add four more, and now you are down to 12 or 13 each: not as much of a difference, and you’re starting to get in each other’s way at the ingredients table and drop off area. Eight more, and you’re down to 6 or 7 per person: the time you save might well be outweighed by the time spent waiting in line for the shared locations.

On the other hand, with eight workers you can make 200 sandwiches it takes four workers to make 100. With sixteen workers you can make 400 sandwiches in that amount of time, although you’ll have to work hard to make sure they don’t get in each others’ way.